Incremental Calculations

SpreadJS provides support for incremental calculation that divides the entire calculation into segments during execution by setting the incrementalCalculation option of the Workbook class to true. This allows for responsiveness to user actions when the calculation task is huge.

You can calculate the cells incrementally and respond to UI events. It prevents the UI from freezing when the workbook contains many formulas. When cells are updated while there are cells pending for calculation, the updated cells along with their dependent cells are added to the calculation tasks. However, the pending calculations are discarded if you insert or delete rows/columns or sheets and the following calculation uses the adjusted formulas.

The incrementalCalculation option, when set to true allows you to track progress updates using the CalculationProgress event.

The following code sample shows how to track progress in the CalculationProgress event.

// This example uses the CalculationProgress event, to log the calculation progress.
spread.options.incrementalCalculation = true;
spread.bind(GC.Spread.Sheets.Events.CalculationProgress, function (e, info) { 
    var msg = "Calculate "; 
    if (info.pendingCells === 0) { 
        msg += "finished"; 
    } else if (info.iterate >= 0) { 
        msg += info.pendingCells + " cells in iterative calculation round " + info.iterate; 
    } else { 
        msg += (info.totalCells - info.pendingCells) + "/" + info.totalCells + "cells"; 
    } 
    console.log(msg); 
}); 

Add Status Bar Item

Incremental calculation is also displayed in the status bar to depict the calculation progress when incrementalCalculation option is set to true.

The following code sample shows how to bind the spread to the status bar, which will automatically display the calculation progress.

// Initialize the status bar and bind it to spread.
var statusBar = new GC.Spread.Sheets.StatusBar.StatusBar(document.getElementById('statusBar'));
statusBar.bind(spread);

For Non-Circular Reference Cells: The progress of calculation is displayed in the percentage format as displayed in the following image:

For Circular Reference Cells: Iterative calculation is implemented by setting iterativeCalculation to true and the progress of calculation is displayed in the iterative rounds as shown in the following GIF.

The following code sample shows how to set iterativeCalculation for Circular Reference.

// Enable IterativeCalculation.
spread.options.iterativeCalculation = true;
spread.options.iterativeCalculationMaximumIterations = 24;